1. Field of the Invention
The present invention relates to a wire guide member that guides an operation wire arranged in a bending portion of an insertion unit.
2. Description of the Related Art
In general, a bending portion of an endoscope is configured by coupling node rings with each other to allow their revolving motion. The bending portion is operated by an operation wire, and this operation wire is inserted into the node rings. Further, each node ring has a holding member (a wire receiving member) that holds the operation wire. This holding member is arranged to improve operability in a pulling operation of the operation wire. The holding member is a cylindrical member welded on, for example, an inner peripheral surface of the node ring. Alternatively, the holding member is formed by cutting and bending the inner peripheral surface of the node ring based on press working.
Further, a wire guide member is inserted in each node ring. The wire guide member is inserted in the holding member (the wire receiving member). At this time, the operation wire is inserted in this wire guide member. The wire guide member avoids interference of the operation wire and any other constituent member and guides the operation wire. The above-described holding member holds the operation wire through the wire guide member.
For example, in Jpn. UM Appln. KOKOKU Publication No. 58-46801, a cylindrical wire insertion hole is arranged in a joint shaft and functions as a holding member (the wire receiving member) that can be linearly or smoothly formed.
Furthermore, Jpn. Pat. Appln, KOKAI Publication No. 2005-237608 discloses a bending portion of an endoscope that compression force of a coil spring is used as resistance so that the bending portion can start bending from a distal end portion thereof. Moreover, Jpn. Pat. Appln. KOKAI Publication No. 2005-237608 discloses the bending portion of the endoscope that a compression rate of the coil spring involved by a bending operation is reduced to prevent a bending operation from becoming heavy and durability of the operation wire is improved.
Additionally, Jpn. Pat. Appln. KOKAI Publication No. 2009-78012 discloses an endoscope that a bending portion can be bent from a distal end side thereof and the bent bending portion can be readily restored.